The most common and most likely answer to this crossword clue is the 17 letter word NAGORONO-KARABAKH
N
A
G
O
R
O
N
O
-
K
A
R
A
B
A
K
H
Buddy explains!
The straight part
We know that "region in Azerbaijan" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case region in azerbaijan = nagorono-karabakh.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.